Well I am one happy gamer with the degree of non-linearity you described.

Now, how much interactivity exists within the game.? By this I mean can I look at things that are interesting though not essential to game completion? Like reading materials or perhaps items within a scene. They may be hints, plot enhancements or just interesting side bits.

There are a lot of items in Alida that pertain to story and are there for that reason and to entice your imagination. Logs, electronic devices, models, decorative wooden devices. My aim was to make sure that the puzzles themselves were objects of intrerest, and not just a means of getting to another level of the game.